1. Field of the Invention
The present invention relates to an apparatus for generating power using wind energy, and more particularly to an apparatus for generating power using wind energy, which includes blades configured to vary in angle by themselves in proportion to the velocity and pressure of wind, thereby being capable of utilizing wind energy at a maximum efficiency.
2. Description of the Related Art
As well known, a large part of energy essentially required by modern society is obtained from fossil fuel. However, there are problems involved with the use of fossil fuel in that fossil fuel is not only limited in availability, but also causes environmental pollution. For this reason, research has been made to develop techniques capable of utilizing inexhaustible clean energy such as solar energy, geothermal energy, wind energy, and tidal energy. A part of those techniques has been advanced to a considerable level of practical use.
Wind energy is the most available inexhaustible clean energy source. For this reason, a variety of structures for utilizing wind energy have been developed.
At the early stage of development, a windmill including blades having an enlarged surface to absorb an increased quantity of wind energy has been proposed. However, such a blade structure has a drawback in that when wind has an excessively high velocity, it may damage the windmill.
In order to avoid damage to windmills due to wind, an improved blade structure has been proposed, in which each of blades has a curved surface while being twisted by a certain angle, thereby being capable of achieving an increase in the efficiency of utilizing wind while obtaining an increased blade stiffness.
However, this blade structure still has a limited resistance to wind force. This problem may be solved by a structure configured to vary in angle in accordance with the velocity of wind. For example, U.S. Pat. No. 4,006,925 discloses a windmill including a slider configured to be slidable along a blade shaft. The slider is retained in position by a tension spring, and is shifted when the centrifugal force generated during a rotation of blades exceeds the tension of the tension spring. The shift of the slider results in a variation in the angle of each blade with respect to wind velocity.
Although the windmill having the above mentioned structure is considered to have a considerable validity in terms of principles, it practically involves a problem in that it cannot achieve a maximum utilization of wind energy because it is very difficult to make the tension of the tension spring retaining the slider be proportional to the centrifugal force generated during the rotation of the blades, thereby causing the range of available wind velocity to be considerably limited.
Another example is disclosed in Korean Patent Laid-open Publication No. 1998-41042. In an apparatus for generating electric power using wind energy, disclosed in Korean Patent Laid-open Publication No. 1998-41042, a torsion spring is mounted to the back surface of each blade. When the blade is subjected to wind of an increased velocity, it is gradually inclined in a rearward direction against the force of the torsion spring. Thus, damage to blades due to increased wind pressure may be prevented.
In the illustrated case, however, there is an inefficiency in terms of the utilization of wind energy because each blade is inclined to be in parallel to the direction of wind. Furthermore, the apparatus may easily be damaged or broken when it is subjected to a severe variation in wind velocity.
Therefore, an object of the invention is to provide an apparatus for generating power using wind energy, which has a configuration capable of automatically adjusting the angle of blades in response to the force of wind applied to those blades, thereby achieving a maximum utilization of wind energy.
In accordance with one aspect, the present invention provides an apparatus for generating power using wind energy, comprising blades for receiving the wind energy, further comprising: a plurality of connecting shafts arranged around a boss and rotatably supported by the boss, each of the connecting shafts extending radially and supporting an associated one of the blades; pinions each fitted around an associated one of the connecting shafts to rotate along with the associated connecting shaft; rack housings each fixedly mounted to the boss near an associated one of the pinions; rack gears each slidably received in an associated one of the rack housings and engaged with an associated one of the pinions; springs each fitted around a portion of an associated one of the rack gears extending beyond the rack housing receiving the associated rack gear and adapted to urge the associated rack gear toward an end of the associated rack gear protruded from the associated rack housing; and spring force adjusting knobs each threadedly coupled to the protruded end of an associated one of the rack gears and adapted to adjust a spring force of an associated one of the springs, whereby each of the blades is angularly shifted about an axis orthogonal to a rotating shaft for the blades in response to a variation in a pressure of wind applied to the blades.
Each of the blades may be eccentrically arranged with respect to an associated one of the connecting shafts.
In accordance with another aspect, the present invention provides an apparatus for generating power using wind energy, comprising blades for receiving the wind energy, further comprising: a plurality of connecting shafts arranged around a boss and rotatably supported by the boss, each of the connecting shafts extending radially and supporting an associated one of the blades; arms each mounted, at one end thereof, to an associated one of the connecting shafts while extending orthogonally from the associated connecting shaft; arc-shaped rods each mounted, at one end thereof, to the other end of an associated one of the arms while extending orthogonally from the associated arm; guide members attached to the boss and adapted to guide respective movements of the arc-shaped rods, respectively, each of the guide members having a guide hole allowing an associated one of the arc-shaped rods to pass therethrough; and springs each fitted around an associated one of the arc-shaped rods between an associated one of the guide members and a flange formed at the other end of the associated arc-shaped rod, whereby each of the blades is angularly shifted about an axis orthogonal to a rotating shaft for the blades in response to a variation in a pressure of wind applied to the blades.
The apparatus may further comprise wind direction sensing means for sensing a variation in the direction of wind applied to the blades, the wind direction sensing means including a vertical shaft, a wind direction indicating member fixedly mounted to an upper end of the vertical shaft and adapted to change an orientation thereof in response to a variation in the direction of wind applied to the blades while correspondingly rotating the vertical shaft, a cam plate mounted to a desired portion of the vertical shaft to rotate simultaneously with the rotation of the vertical shaft, and a micro switch adapted to come selectively into contact with a periphery of the cam plate in accordance with the rotation of the cam plate, thereby generating an electrical signal; pivoting means for pivoting the rotating shaft in response to the wind direction variation sensed by the wind direction sensing means, thereby changing an orientation of the blades, the pivoting means including a housing arranged to support the rotating shaft while being rotatable in response to the wind direction variation to change an orientation of the rotating shaft, and an electromagnet activated by the electrical signal from the micro switch to change an orientation of the rotating shaft; and braking means for restraining the rotation of the housing in response to the activation of the electromagnet.